The long-term goal of this research project is to better understand the neural mechanisms that control the voice. Presently, the acoustic variables of auditory feedback related to vocal control are poorly understood. Pilot data indicate that perturbations in frequency of tone feedback cause reflexive adjustments in voice fundamental frequency (F0) output, but vocal responses appear less prevalent and smaller in magnitude than responses elicited to perturbed voice feedback. The specific objective of this project is to assess the acoustic parameters of non-voice (tone) auditory feedback that are important for voice F0 control across acoustic dimensions of (1) fundamental frequency, (2) harmonic complexity, and (3) intensity. It is hypothesized that voice F0 response prevalence and magnitude to perturbations in pitch of tone feedback are dependent upon the similarity between the acoustic properties of auditory feedback and the voice. This hypothesis will be tested using the pitch-shift paradigm to elicit voice F0 responses (pitch-shift reflex) to perturbations in pitch of voice or tone auditory feedback. Subjects will vocalize at a sustained voice F0 while hearing their voice or tone auditory feedback over headphones. Small magnitude, short duration perturbations in pitch will be randomly introduced into the feedback during each vocalization, and event-related averages will be calculated across multiple vocalizations for each subject. Voice F0 response prevalence, magnitude, and latency will be measured and compared across experimental conditions. This project will provide valuable information about the neural control of the voice by identifying acoustic components (fundamental frequency, harmonics, and intensity) of voice and non-voice feedback that may be important for modulation of voice fundamental frequency. [unreadable] [unreadable] The application proposes a dissertation study of motor control of voice. In particular, the pitch-shift response will be studied in three experimental directions with respect to each of three dimensions, fundamental frequency, harmonic complexity, and intensity. This area of investigation has been receiving greater attention in recent years, which supports the applicant's claim that these isolated parameters require more specific understanding of their action. The candidate's strength in neuroscience training assures that the control mechanisms underlying these phenomena will receive adequate attention. [unreadable] [unreadable]